Showing papers in "Mycologia in 1999"

A method for designing primer sets for speciation studies in filamentous ascomycetes

Abstract: A simple method is described for designing primer sets that can amplify specific protein-encoding sequences in a wide variety of filamentous ascomycetes. Using this technique, we successfully desig...

Batrachochytrium dendrobatidis gen. et sp. nov., a chytrid pathogenic to amphibians

Abstract: Captive and wild frogs from North and Central America and Australia recently have died with epidermal infections by chytridiomycete fungi. We isolated a chytridiomycete into pure culture from a captive, blue poison dart frog that died at the Na- tional Zoological Park in Washington, D.C. Using this isolate, we photographed developmental stages on nutrient agar, examined zoospores with transmission electron microscopy, and inoculated test frogs. This inoperculate chytrid develops either monocentrically or colonially and has thread-like rhizoids that arise from single or multiple areas on the developing zoo- sporangium. The taxonomically important features of the kinetosomal region of the zoospore indicate that this chytrid is a member of the Chytridiales but differs from other chytrids studied with transmission electron microscopy. Its microtubule root, which be- gins at kinetosome triplets 9-1 and extends parallel to the kinetosome into the aggregation of ribosomes, is distinctive. Histologic examination of test frogs re- vealed that the pure culture infected the skin of test frogs, whereas the skin of control frogs remained free of infection. The fungus is described as Batrachochy-

Cochliobolus phylogenetics and the origin of known, highly virulent pathogens, inferred from ITS and glyceraldehyde-3-phosphate dehydrogenase gene sequences.

Abstract: We evaluate the phylogenetic distribution of known, highly virulent plant pathogens in the genus Cochliobolus (sexually reproducing species in the Ascomycota, Pleosporaceae) and assess the relation...

Saprotrophic cord-forming fungi: meeting the challenge of heterogeneous environments

Abstract: Many saprotrophic fungi, especially basidiomycetes, which are able to grow out of the substratum that they are colonizing in search of new resources (i.e., nonresource-unit-restricted fungi) form m...

Morphological and molecular characterization of Fusarium pseudograminearum sp. nov., formerly recognized as the Group 1 population of F. graminearum

Abstract: Fusarium pseudograminearum sp. nov., formally known as F. graminearum Group 1, is described and illustrated. Fusarium pseudograminearum can be distinguished from F. graminearum based on difference ...

Classification of the mycoparasite Gliocladium roseum in Clonostachys as C. rosea, its relationship to Bionectria ochroleuca, and notes on other Gliocladium-like fungi

Abstract: Because the common soil fungus and mycoparasite Gliocladium roseum differs from the type species of Gliocladium, G. penicillioides, in morphology, ecology, teleomorph, and DNA sequence data, it is ...

A microtiter plate procedure for evaluating fungal functional diversity

Abstract: A method (FungiLog) was developed that allows a quantitative approach to examining aspects of fungal functional diversity. The BIOLOG microti- ter plate method for measuring bacterial functional diversity was modified for use with fungal assemblag- es. Each BIOLOG plate contains 95 different carbon substrates. Eight different tetrazolium dyes were eval- uated and dimethylthiazolyl-diphenyltetrazolium bro- mide (MTT) was chosen as the most suitable indi- cator of fungal growth. Procedures for inoculum preparation from a variety of substrates and inocu- lation into modified BIOLOG SF-N microplates were devised. By also plating out inoculum used to inoc- ulate the FungiLog plates, taxonomic data can be ob- tained in conjunction with functional diversity. The FungiLog method was subsequently evaluated for de- tecting landscape patterns of fungal functional diver- sity using decaying lechuguilla (Agave lechuguilla) leaves placed along an elevational gradient in Big Bend National Park, Texas, in 5 vegetation zones. Sites ranged from a high elevation (2098 m) zone dominated by live oak (Quercus emoryi) and pinyon pine (Pinus cembroides) to a low land Chihuahuan Desert scrub (973 m). Ten, preweighed, 10-cm pieces of lechuguilla leaves were collected from each vege- tation zone, 5 per transect, after 6 mo decomposi- tion. FungiLog data were used to calculate two mea- sures of fungal functional diversity, substrate richness and total activity. FungiLog patterns distinguished differences in total activity and substrate richness among the low elevational and the high elevational sites at this stage in the decomposition of lechuguilla leaves. Furthermore, litter decomposition was greater

Genome sizes of Epichloe species and anamorphic hybrids

Abstract: Several Neotyphodium species (asexual fun- gal symbionts of grasses) have been characterized ge- netically as heteroploids (nonhaploids) derived by in- terspecific hybridization involving sexual Epichloiespe- cies (Clavicipitaceae, Hypocreales). Examples in- clude Neotyphodium coenophialum with at least three ancestral Epichloe species, and a rare endophyte of perennial ryegrass that appears to be a hybrid of Ep- ichloe typhina with the common perennial ryegrass endophyte, Neotyphodium lolii. In contrast, N. lolii ap- pears to be haploid and closely related to Epichloe festucae. Hypothesizing that hybrid origins should re- sult in larger genome sizes, we estimated genome siz- es for two Epichloe and three Neotyphodium spp. Using quantitative Southern blot hybridization we estimat- ed genome sizes of 29 ? 4 Mb for two sexual hap- loids, E. festucae isolate E189 and E. typhina E8. Es- timates for hybrid anamorphs were 57 ? 7 Mb for N. coenophialum el9, and 55 ? 7 Mb for N. lolii X E. typhina Lpl. Electrophoretic karyotyping of these four isolates corroborated the genome size estimates. Also, the electrophoretic karyotype of N. lolii isolate e45 indicated a genome size similar to that of the Epichloe species, in keeping with the apparent non- hybrid nature of N. lolii. Genome size differences were reflected in the variation of conidium lengths and widths suggesting that large conidial size may be an indicator of heteroploidy and, therefore, possible

Molecular phylogeny of the cleistothecial fungi placed in Cephalothecaceae and Pseudeurotiaceae

Abstract: Ample evidence from both morphological and molecular characters has accumulated to establish that the cleistothecial ascoma has been derived independently on different occasions from perithecial an...

Molecular systematics of the Herpotrichiellaceae with an assessment of the phylogenetic positions of Exophiala dermatitidis and Phialophora americana

Abstract: Despite a significant body of evidence in support of the close phylogenetic relationship of species of Capronia (Herpotrichiellaceae) and black yeasts belonging to or allied with the genus Exophiala questions concerning the taxonomic importance of features furnished by ascospore, stromal and anamorph characters have remained unanswered. In order to address these issues and to elucidate more fully relationships within the family, we have sequenced a portion of the nuclear large ribosomal RNA subunit (28S), the 5.8S gene, and the internal transcribed spacers (ITS1 and ITS2) of 15 species of Capronia and 19 black yeasts assigned to the form genera Cladosporium, Cladophialophora, Exophiala, Fonsecaea, Phaeococcomyces, Phialophora, Ramichloridium and Rhinocladiella. Cladistic analysis of these data confirmed the monophyly of the Herpotrichiellaceae but did not support the division of the genus Capronia on the basis of conidial ontogeny, pattern of ascospore septation, or the degree of stromal development. Homothallic species of Capronia with 8-spored asci, muriform ascospores and Exophiala anamorphs formed a well-supported lineage that included the medically important species Exophiala dermatitidis. Capronia mansonii and Capronia munkii, morphologically similar taxa isolated from the wood of Populus, were inferred as closely related but separate species. The clade comprising members of the Herpotrichiellaceae that possess Cladosporium-like and Phialophora anamorphs was also strongly supported. Available molecular evidence indicates that Dictyotrichiella semiimmersa and Phialophora americana are teleomorph and anamorph states of a single holomorph. Cladistic analysis also confirmed that the genera Cladophialophora and Ramichloridium are polyphyletic. The anamorphs of Capronia nigerrima and Dictyotmchiella semiimmersa are described and illustrated, and the combination Capronia semiimmersa is proposed.

Phylogenetic relationships of cantharelloid and clavarioid Homobasidiomycetes based on mitochondrial and nuclear rDNA sequences

Abstract: Sequence data from mitochondrial and nuclear small subunit rDNA were used to estimate phylogenetic relationships of cantharelloid and cla- varioid Homobasidiomycetes. Sixty-five diverse Homobasidiomycete species were investigated, in- cluding 23 cantharelloid and clavarioid species. Al- though nodes deep in the tree could not be resolved, four lineages containing cantharelloid and clavarioid fungi were identified. (i) Cantharellaceae (Canthar- ellus, Craterellus) is closely related to Hydnum, which is toothed, Stichoclavaria, which is a simple club, and Clavulina, which is coralloid. These taxa all have stichic nuclear division, which is a synapomorphy supporting this clade. (ii) Clavariadelphus is closely related to Gomphus and Ramaria. This relationship is supported by green reactions of sporocarps treated with iron salts, which is reflective of the presence of the compound pistillarin. The nearest relatives of these cantharelloid and clavarioid fungi are gastero- mycetes, including the earth star Geastrum, the stink- horn Pseudocolus, and the "cannon-ball fungus" Sphaerobolus. (iii) The clavarioid fungi Clavaria, Cla- vulinopsis, Pterula, and Typhula appear to be derived from the lineage that contains most of the gilled fun- gi. (iv) Clavicorona is closely related to Auriscalpium, which is toothed, and Lentinellus, which is gilled. This lineage is united by amyloid spore ornamenta- tion. Although these results suggest that there has been extensive convergence in fruiting body mor- phology, certain anatomical and biochemical features appear to be phylogenetically informative, notably stichic nuclear division, presence of pistillarin, and cyanophily or amyloidity of spore ornamentation.

Partial beta -tubulin gene sequences for evolutionary studies in the basidiomycotina

Abstract: Four primer pairs comprising six individ- ual primers were used to amplify regions of 3-tubulin genes from members of the Basidiomycotina. A re- gion of approximately 500 bp, spanning two introns and 133 codons, was PCR-amplified and sequenced from isolates of Lentinula spp., Pleurotus spp., and several related taxa. Intronic regions were highly polymorphic among Pleurotus spp. and between Pleu- rotus and Lentinula. Two L. lateritia isolates were 99% similar to each other and 80.7%-82.8% similar to Pleurotus species. Sufficient polymorphism also ex- isted within protein coding regions to differentiate among species of Pleurotus. Lentinus tigrinus and Ganoderma lucidum shared a unique evolutionary lin- eage. The phylogenetic analysis provided evidence for an ancient gene duplication among ascomycete genes. The basidiomycete lineage is attached at a point near the Aspergillus nidulans BenA/Colletotri- chum graminicola Tub2 cluster, after the divergence of the gene duplication. The existing level of varia- tion among the fungi examined indicates that this gene will be useful in phylogenetic investigations of higher order relationships among broader groups of fungi.

Molecular phylogeny of amanita based on large-subunit ribosomal dna sequences: implications for taxonomy and character evolution

Abstract: Phylogenetic relationships in the genus Amanita were investigated using sequence data from the nuclear-encoded large subunit ribosomal DNA. Exemplar taxa were selected to represent the all sec- tions from the current classifications of Singer, Bas and Jenkins. Phylogenetic analysis of the nuc-LSU re- gion supports the taxonomic distinction of subgen- era Amanita and Lepidella, as well as all nine sections previously recognized by Singer (R. Singer, 1986, The Agaricales in Modern Taxonomy, 4th ed.) including sections Amanita, Amidellae, Caesareae, Lepidella, Mappae, Phalloideae, Ovigerae, Vaginatae, Validae. Phylogenetic analyses among these nine terminal groups reveal several higher-level relationships which are also supported by morphological and biochemi- cal characters. A phylogenetic classification is pro- posed which recognizes two subgenera (Amanita, Lepidella), four sections (Amanita, Vaginate, Phallo- ideae, Lepidella), seven subsections (Amanita, Oviger- ae, Amidellae, Caesareae, Phalloideae, Vaginatae, Vali- dae), and two series (Mappae, Validae).

Three new species of Epichloë symbiotic with North American grasses.

Abstract: The genus Epichloi sensu stricto includes several mating populations (biological species) of en- dophytic fungal symbionts of cool season grasses. To date, six Eurasian and one North American mor- phospecies have been described, and these approxi- mately correspond to six distinct mating populations. Here we describe three additional Epichloe species found in natural symbioses with grasses native to North America. In mating tests the three species were not interfertile with each other or any previously de- scribed Epichloe species. Sequences of (3-tubulin gene introns, which have been useful for Epichloe phylo- genetics, clearly distinguished the three species, iso- lates of each constituting a well supported clade. The three new species were host specific: E. brachyelytri was naturally associated only with Brachyelytrum erec- tum, E. elymi only with Elymus species, and E. glyceriae only with Glyceria striata. While most morphological characteristics of E. elymi and E. glyceriae were typical of the genus, the ascus structure of E. brachyelytri was unique among described Epichloe species. Vertical transmission by systemic infection of host seeds was common for E. brachyelytri and E. elymi but never occurred for E. glyceriae. Conversely, E. glyceriae de- veloped stromata on every infected host inflores- cence (preventing its maturation), E. elymi produced

The Cylindrocladium candelabrum species complex includes four distinct mating populations

Abstract: Cylindrocladium candelabrum-like isolates were collected from a wide variety of geographic lo- cations and compared based on their morphology, sexual compatibility and the nucleotide sequences of their rDNA ITS regions. All isolates included in this study mated to produce Calonectria teleomorphs with viable progeny. Four distinct mating populations were identified, each representing a genetically iso- lated, biallelic, heterothallic population. Several rep- resentative isolates of each mating population, re- flecting geographic diversity, were chosen for se- quence comparisons. The internal transcribed spacer (ITS) regions 1 and 2 that flank the 5.8S rDNA gene, as well as the gene itself, were sequenced and com- pared. All isolates representing the same group yield- ed similar sequences, but small, consistent differenc- es were found between the groups. Based on these results we recognise Calonectria scoparia (anamorph Cylindrocladium candelabrum), and describe three new species, namely Calonectria pauciramosa (ana- morph Cylindrocladium pauciramosum), Calonectria insularis (anamorph Cylindrocladium insularae) and Calonectria mexicana (anamorph Cylindrocladium mexicanum).

Patterns of geographic speciation in the genus Flammulina based on sequences of the ribosomal ITS1-5.8S-ITS2 area

Abstract: Previous studies based on morphology and on ability to intercross suggested that new bio- logical and morphological species were sheltered within the genus Flammulina as well as varieties with- in E velutipes. The currently described or proposed Northern Hemisphere Flammulina species are F "mexicana, "F. populicola, F rossica, F ononidis, E elas- tica, F. fennae and F velutipes. Within E velutipes are F velutipes var. velutipes, var. " lupinicola," and var. lac- tea. The ribosomal ITS1-5.8S-ITS2 region was se- quenced for eighteen geographically diverse Flam- mulina collections, including the three F velutipesva- rieties. Results of neighbor-joining and parsimony analysis produced five distinct Northern Hemisphere clades, a clade consisting of F velutipes together with it's varieties, a clade consisting of F populicola and F. "mexicana", and clades representing F fennae, F. ros- sica and F elastica together with F. ononidis. Data are consistent with the hypothesis that F. populicola is a relatively old species which has diverged significantly on different continents, possibly giving rise to F "mexicana" in North America. The ITS sequence for Flammulina stratosa, an isolate from New Zealand, is highly divergent from all other Flammulina isolates and may represent an ancient endemic or the prod- uct of very rapid evolution. Species diversity is high-

Evidence supporting the occurrence of a new species of endophyte in some South American grasses

Abstract: Endophytes of several South American grasses were examined. The taxonomic status of en- dophytes in Festuca argentina, E hieronymi, Poa hue- cu, and an unidentified species of Poa is evaluated. On the basis of morphological features, and rDNA and protease gene sequence data, it is proposed that this endophyte is different from several other endo- phytes examined from North American, South Amer- ican, and European species of Festuca and Poa. These endophytes, believed responsible for causing the 'tembladera' or 'huecu' toxicosis in animals, have also been reported to produce unique toxins. Iso- zyme analysis supports the distinctness of these en- dophytes but also demonstrates variability in popu- lations with respect to gene polymorphisms. Taking all the data into consideration, we propose to estab- lish a new endophyte species Neotyphodium temblad- erae which includes endophytes found in multiple grass species. We suggest the use of a phylogenetic species concept to define species of Neotyphodium.

Phylogenetic relationships within Lepiota sensu lato based on morphological and molecular data

Abstract: Current classifications of the light-spored agaric genus Lepiota s. 1. (Agaricaceae, Agaricales) were evaluated using parsimony analyses of morphological and molecular characters. Thirty-ei...

Phylogenetic subgrouping of Rhizoctonia solani AG 2 isolates based on ribosomal ITS sequences

Abstract: In Rhizoctonia solani differences in the se- quences of ribosomal DNA correlate with differences in habitat and virulence. All the current data agree for a completely conserved 5.8 S region, but show variation in both internal transcribed spacers (ITS) regions. This variation in size and nucleotide se- quence, in general, is proportionately greater within isolates with greater differences in anastomosis com- patibility, pathogenicity and habitat. Rhizoctonia so- lani AG 2 is geographically widespread and consists of several anastomosis subgroups with specific path- ogenic behavior. To obtain insight in the phyloge- netic relations among subgroups, and between sub- groups and geographically separated isolates, the complete DNA sequences of the ITS regions of 31 isolates of Rhizoctonia solani AG 2 and one isolate

Phylogeny of Cryphonectria cubensis and allied species inferred from DNA analysis

Abstract: Cryphonectria cubensis causes a serious canker disease of Eucalyptus in many tropical areas of the world. The aim of this study was to determine the phylogenetic relationships among strains of C. c...

Gene flow analysis of molecular markers confirms that Phytophthora mirabilis and P. infestans are separate species

Abstract: The taxonomic status of Phytophthora mir- abilis, one of six host-specific, foliar pathogens in Phy- tophthora group IV, has been uncertain. At various times this taxon has been given three different names: P infestans var. mirabilis; P mirabilis; and P infestans forma specialis mirabilis. Which of these names is correct depends on the degree of repro- ductive isolation between this taxon and the closely related species, P infestans. The purpose of this pa- per was to evaluate the hypothesis that P infestans and P mirabilis are conspecific using a large battery of molecular markers. Analyses of one isozyme, 44 DNA fingerprint, and 85 presumed RAPD loci re-

Teleomorph-anamorph connections: the new pyrenomycetous genus Carpoligna and its Pleurothecium anamorph

Abstract: Several collections of a pyrenomycete identified as Chaetosphaeria were made from decor- ticated wood of twigs and branches in Costa Rica, Panama, Puerto Rico and continental USA. Discrete and continuous characters of the ascomata, asci and ascospores in these collections show that they are very similar morphologically and represent popula- tions of the same species. However, culturing of sin- gle ascospore isolates from these collections yielded an anamorph unlike the typical phialidic anamorphs of Chaetosphaeria. This anamorph fits the description of Pleurothecium recurvatum, for which a teleomorph connection has not been yet established. Sequences of the ITS region of the nuclear ribosomal DNA of three collections from Costa Rica, Puerto Rico and USA were compared and found to be 98% similar. Parsimony and maximum likelihood analyses of se- quences of the large subunit nuclear-encoded ribo- somal DNA from representative taxa of eight asco- mycetous orders show this ascomycete as a monophy- letic group distinct from Chaetosphaeria. Statistical analyses of hypothetical trees based on the most par- simonious and the most likely trees rule out phylo- genetic affinities of this pyrenomycete to Chaetos- phaeria. These analyses suggest possible affinities to the Hypocreales and/or the Microascales. Based on morphology of the anamorph and analyses of ribo- somal DNA sequence data, Carpoligna pleurothecii gen. et sp. nov. are described. The implications of the phylogenetic relationships of Carpoligna in the practical identification of morphologically similar pyrenomycetes are discussed.

Phomopsis amygdali causes peach shoot blight of cultivated peach trees in the southeastern United States

Abstract: Phomopsis shoot blight of peach is an in- creasingly common fungal disease in southeastern peach growing areas of the United States. A similar disease has been reported from Europe where it oc- curs on both peach and almond. Strains of Phomopsis were obtained from peach, asian pear and plum in the United States and from almond in Spain and It- aly. Examination of the morphological, cultural and molecular characteristics of these strains showed that the Phomopsis amygdali on almond in Europe is the same as the fungus found on peach in the USA. The species of Phomopsis on plum and asian pear in the United States is different from P amygdali.

Tilletia walkeri, a new species on Lolium multiflorum and L. perenne

Abstract: Tilletia walkeri (Ustilaginales: Tilletiaceae) is described as a new species of partial bunt infecting Lolium multiflorum, annual ryegrass, and L. perenne, perennial ryegrass in the United States and Australia, respectively. The new species is characterized by large, tuberculate teliospores with the exospore or- namentation comprised of incompletely cerebriform ridges in surface view. Teliospores of T. walkeri are compared with those of T. indica and other similar species of Tilletia, and the issue of Neovossia versus

Trichomycetes in Argentinean aquatic insect larvae

Abstract: Investigations of larval aquatic Diptera (Chironomidae, Simuliidae, Culicidae), Coleoptera (Scirtidae), and Plecoptera (Gripopterygidae, Notonemouridae) in Buenos Aires Province and three Provinces...

Phylogenetic studies within the Pezizales. I. 18S rRNA sequence data and classification

Abstract: The order Pezizales has been divided into two suborders. One suborder, the Sarcoscyphineae, was originally described to include members whose asci were characterized by an unusual apical structure,...

Sterols and fatty acids of the Mortierellaceae: taxonomic implications

Abstract: The total sterols of selected Mortierella species were analyzed by GLC/MS with the aim of determining if the distribution of major sterols followed taxonomic lines within the zygomycetous family Mo...

Molecular phylogenetic analysis of Peziza and related genera

Abstract: In a previous study of the genus Plicaria and its relationship to Peziza, the molecular phylog- eny that was generated suggested Peziza is paraphy- letic. The objective of this study was to explore this problem by examining a larger sample of Peziza spe- cies, by increasing the length of DNA sequence ana- lyzed, and by including in the analysis additional gen- era in the Pezizaceae. DNA sequences were obtained from the 5' internal transcribed spacer region, the divergent domains D1 and D2 of the 28S gene, and most of the 18S gene of the nuclear-encoded ribo- somal DNA. Maximum-likelihood analysis of these se- quences indicates that Peziza is composed of at least two distinct clades: the first clade contains taxa with mostly smooth to finely-roughened, eguttulate asco- spores and Oedocephalum anamorphs, the second clade contains mostly taxa with warted, guttulate as- cospores and Chromelosporium anamorphs. Separate generic status for Kimbropezia is weakly supported by the phylogenetic analysis and Peziza quelepidotia is sufficiently distinct to retain its original status as Lep- idotia hispida. This study is the first to suggest a phy- logenetic link between the mitotic fungus Glischrod- erma, and the genera Scabropezia and Pachyphloeus. Other hypogeous species that belong in the Peziza- ceae include Cazia flexiascus, Terfezia arenaria and